Integration tests - Phase 1

[zvecr]

Description

Longer term, it has been decided that building all keyboards is not a maintainable strategy for CI. Instead more effort is to be put into unit tests, and running a subset of scenarios. This PR aims as an initial first pass to encapsulate these "integration" test cases. Rather than tag folders within the keyboard structure, I figured it was cleaner to start a new dedicated folder (however this is totally up for discussion).

First pass is to enable such testing, so that the selection of scenarios can begin to be collated. I imagine a structure that migrates away from the current handwired/onekey with its multiple keymaps and something like

examples/<feature>/<dev_board>/

maybe some structure around software/hardware/driver

TODO:

• it folder name, e2e/integration/? Going with examples per discord discussion
• work out better magic for make/qmk cli (right now its a bodge with KEYBOARD_DIR=it make onekey:default)

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).